A redescription of Tenagomysis species and Gastrosaccus australis from estuarine environments (Crustacea: Mysida) in Auckland region, New Zealand

Investigation of mysid habitats in estuarine waters were conducted at 59 sites throughout Auckland region from May 2006 to January 2009. This paper provides the taxonomic descriptions of the three species, collected during this survey. Among the 59 sites mysids were collected only at 26 sites: Tenagomysis chiltoni collected from 15 sites, T. novaezealandiae from 21 sites and Gastrosaccus australis from four sites. Ontogenetic variation observed in the size of the antennal scale, and counts of lateral spines and cleft spines of telson and uropod for both T. chiltoni and T. novaezealandiae. Such apparent characteristics should not be used alone to differentiate species. It is important to use a combination of characteristics such as shape of the rostrum, anterolateral margin of the carapace, number of articulations of carpo-propodus of thoracic limbs and shape and size of the antennal scale. Several aspects of the description of T. chiltoni provided by Tattersall (1923) and Hodge (1964), do not agree with the present specimens, this is due to size variations.